https://manuals.plus/tidradio/td-h3-two-way-radio-manual
This is more helpful than the booklet. I hate tiny booklets.
"1750Hz Repeater Tone (R-TONE) – Menu No.32
With this function you can select IO00Hz, l 450Hz, l 750Hz, 2100Hz repeater tone. To send out a repeater tone; You hold down the [PTT] + [ LAMP ] key.
If you have the keypad lock enabled on your radio, you can still send al 750Hz tone the regular way without having to unlock your radio."